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Pseudo-von Willebrand syndrome is congenital thrombocytopathy in which the platelet GP Ib receptor is defective, resulting in increased affinity for vWF. Most patients experience bleeding from the mucous membranes (nose, gums, gastrointestinal tract). Bleeding from the uterus is also frequent, after tooth extraction, as well as after injuries and childbirth.
The alleged von Willebrand syndrome – what is it?
Pseudo-von Willebrand syndrome is the most common thrombocytopathy (bleeding disorder) characterized by blood clotting disorders. The disease was first described in 1968 in a seven-year-old boy with systemic lupus erythematosus. The ailment may therefore manifest itself in prolonged or excessive bleeding. The occurrence of von Willebrand syndrome is associated with impaired function of von Willebrand factor, i.e. a protein that is found in our bloodstream and is necessary for blood clotting. In addition, a defect of this factor prevents platelets from sticking to each other and the edges of the wound, making it impossible to stop bleeding. The alleged von Willebrand syndrome is much more common than type A and type B hemophilia combined. The disease often develops in the course of other ailments, such as lymphoproliferative diseases, myeloproliferative diseases, cardiovascular diseases, autoimmune diseases, in some non-haematological neoplasms and after the use of certain preparations. The pathogenesis of this syndrome is complex and has not been fully understood. The diagnostic basis is the assessment of the concentration and activity of vWF in plasma and the analysis of multimers. In contrast, treatment is based on the treatment of comorbidities and the prevention of edges. Drugs in the form of concentrates containing vWF and intravenous immunoglobulins, and auxiliary – antifibrinolytic preparations are used most often.
What are the causes of von Willebrand syndrome?
When talking about the causes of this ailment, it is necessary to distinguish its various types:
- type 1 (mild) syndrome – is the most common type of disease, which may affect up to 70% of all cases. The cause of its formation is usually a minimal deficiency of von Willebrand factor. The mild type is inherited autosomal dominant, which means that one normal copy is inherited and one defective copy of the gene is inherited and becomes more important than the normal copy. The disease is more common in the female sex;
- type 2 syndrome (qualitative) – here the von Willebrand factor is produced in appropriate amounts, but its function is disturbed. As with type 1, the disease may be inherited in an autosomal dominant or recessive manner;
- type 3 syndrome (severe form) – patients have a complete deficiency of von Willebrand factor. Type 3 is inherited autosomal recessively, and patients with this type of disease are usually descendants of parents with type 1.
It is worth mentioning that von Willebrand syndrome can also have an acquired character, similar to congenital syndrome. In the case of acquired disease, the deficiency or disturbance of the vWS factor occurs due to the action of autoantibodies directed against the factor. Acquired von Willebrand syndrome occurs later, often accompanying other diseases, e.g. non-haematological neoplasms or diseases of the cardiovascular system. Unfortunately, despite the presence of clinical symptoms, the disease often remains undiagnosed
Symptoms of the alleged von Willebrand syndrome
The most common symptoms of this ailment are:
- tendency to bruise easily;
- nose bleeds
- bleeding gums
- plentiful and prolonged menstruation,
- gastrointestinal bleeding
- bleeding after surgery,
- postpartum bleeding,
- bleeding after injuries.
The course of type 1 of pseudo-von Willebrand syndrome is usually mild, and symptoms are present in approximately 65% of patients. By contrast, in type 2, the bleeding involved is variable, although generally moderate in nature. In type 3, in addition to the presence of edges, an increased tendency to bruise is observed.
Note: Women with heavy periods and need to change tampons / pads more than once an hour should consult their doctor and check for von Willebrand syndrome.
Von Willebrand syndrome – diagnosis
The following tests are carried out in people with suspected von Willebrand syndrome:
- screening test (basic) in the form of blood count with platelet count and coagulogram, i.e. PT (prothrombin time);
- assessment of factor VIII activity, ristocetin cofactor activity and von Willebrand factor concentration.
Patients with the third type of disease are diagnosed with prolonged bleeding time (more than twenty minutes) and decreased activity of factor VIII and Willebrand antigen. In addition, a decreased activity of the cofactor ristocetin is observed. On the other hand, in disease types 1 and 2, the bleeding time, factor VIII and Willebrand factor levels are normal (however, the activity of the cofactor ristocetin is reduced).
Von Willebrand syndrome – treatment
Treatment of the disease is aimed at:
1) inhibition of bleeding,
2) prevention of bleeding in the event of a high risk of haemorrhage (e.g. in the case of an urgent invasive procedure);
3) achieving (if possible) remission of the underlying disease in the course of which AvWS developed.
Typically, patients are given desmopressin, a preparation that releases von Willebrand factor into the blood. Moreover, deficiencies of vWD factor are replaced in patients by administering plasma-derived factor VIII concentrates. In addition, the therapy uses preparations supporting clotting, as well as hormonal and local drugs, whose task is to close the external wound.
Lit.: [1] Russell S.D., Roth G.J.: Pseudo-von Willebrand disease: a mutation in the platelet glycoprotein Ib?ż gene associated with a hyperactive surface receptor. Blood 1993, 81; 1787-91. [2] Matsubara Y., Murata M., Sugita K. i wsp.: Identification of novel point mutation in platelet glycoprotein Ib?ż, Gly to Ser at residue 233, in Japanese family with platelet-type von Willebrand disease. J Thromb Haemost 2003, 1; 2198-205.
Source: A. Kaszuba, Z. Adamski: “Lexicon of dermatology”; XNUMXst edition, Czelej Publishing House